Geoscience Reference
In-Depth Information
Chapter 2
Remote-Sensing Technologies and Data
Processing Algorithms
2.1 Remote Sensing Methods
Remote sensing of the land covers, atmosphere and World Ocean aquatories is
based on the registration of background or re
ected and scattered electromagnetic
radiation. Such knowledge is necessary to get data about the properties of envi-
ronmental elements as it explains the dependence of thermal emission on its own
physical and geothermal parameters. Also the scattering mechanisms and active
radiation re
fl
ection are functions of these parameters (Borodin 2008; Bui Ta Long
1998; Shutko et al. 1994, 2010; Krapivin and Shutko 2002, 2012; Petty 1995;
Schimel 1995; Golovachev et al. 2004; Cheremisin 2013; Savinikh et al. 2007).
The waves (or frequencies) of electromagnetic emission used for remote sensing
in environmental monitoring systems occupy a wide spectrum from 0.3
fl
μ
m to 1.3 m
and cover the subranges: near ultraviolet (0.3
0.4
μ
m), visible (0.4
0.76
μ
m), near
-
-
infrared (IR: 0.76
1.5
μ
m), middle and far IR (1.5
μ
m
1 mm), super high frequency
-
-
(SHF: 1 mm
1.3 m). The SHF-range is divided into three basic subranges: milli-
-
meters (1
10 mm), centimeters (1
10 cm), and decimeters (10
130 dm). Two sub-
-
-
-
ranges called usually as L-band (15.8
-
63 cm) and P-band (63
-
100 cm) are used by
many authors.
The real range choosed for objective study of the environment has to take on
board many conditions such as the absorption and scattering of electromagnetic
waves by the Earth
s land covers
and water surfaces. The atmosphere is an extremely limiting factor when choosing a
working range for remote monitoring. For instance, the P-band can used for abyssal
sensing from the
'
s atmosphere and its interactions with the Earth
'
flying laboratories, but its application in satellite monitoring
systems is beset with problems because the ionosphere acts as a screen. A similar
situation is found with ultraviolet radiation which is intensively absorbed by
atmospheric gases. In order words, there is a question about the atmosphere clarity
for speci
fl
c wavelengths. For example, some wavelengths in the IR and submilli-
meter ranges are intensively absorbed by water vapor which practically precludes
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